Glass Failure in Miami High-Rises Shocks Experts

[Wacahootaman]

Glass failure in high-rises shocks experts

High-rise windows in Miami-Dade and Fort Lauderdale did not live up to safety expectations, leaving experts wondering what went wrong.

BY CURTIS MORGAN AND MATTHEW HAGGMAN

cmorgan@herald.com

Wilma was the first real test in decades of how the glittering, fast-growing skylines of Miami and Fort Lauderdale would hold up in a hurricane. The result stunned and troubled emergency managers and building experts.

Hundreds of windows blew out in dozens of high-rises, causing extensive and expensive damage to such centers of public life as the Broward County Courthouse and heralded new Miami landmarks such as the Espirito Santo Plaza and Four Seasons Tower.

On Tuesday, panes were still falling from the posh Miami hotels, recently completed under the strictest building and wind codes. They posed such a public safety danger that Miami police closed five blocks of Brickell Avenue to traffic.

''This looks like Berlin after the war,'' said Miami Police Chief John Timoney, as he surveyed more than a half-dozen ravaged buildings on Brickell. ``I don't know what to make of it. These buildings are supposed to resist winds up to 150 miles per hour.''

The destruction perplexed structural engineers and contractors as well, who were groping for causes that may not be pinpointed until inspectors and engineers examine each structure.

Some pointed to one obvious suspect -- an assault of wind-driven debris, perhaps gravel from surrounding high-rise roofs or trash from surrounding construction sites -- but there were many possibilities.

In older buildings, it could be as simple as glass never designed to withstand hurricane winds. In newer ones, it might be anything from poor construction techniques to faulty materials to specific designs of some buildings to the dynamic of wind moving among buildings and possibly ''tunneling,'' or multiplying, its force.

`DUMBFOUNDED'

No less of a construction authority than Herb Saffir, a Coral Gables structural engineer who co-developed the Saffir-Simpson scale used to rate hurricane intensity, pronounced himself ''dumbfounded'' by the widespread window losses -- particularly to newer downtown Miami buildings such as the JW Marriott hotel, constructed after Miami-Dade beefed up its building codes following Hurricane Andrew in 1992.

Wilma, Saffir pointed out, wasn't even a major hurricane when it hit the Southeast coast, but a Category 2 or even 1. The highest reported gusts in downtown Fort Lauderdale barely topped 100 mph. Downtown Miami got off even lighter.

''Even if it had been the pre-Andrew code, I think those windows should have stayed in place,'' he said.

http://www.miami.com/mld/miamiherald/12996051.htm

[dhweather]

So much for those superior miami-dade codes.

[Canelaw99]

Well, maybe for the skyscrapers. If you look at most neighborhoods though, the buildings themselves are fine. There may be damage due to a tree falling into a house, or windows damaged if not boarded, but for the most part S. FL buildings (office bldgs. excluded) held up well under Wilma.

[donsutherland1]

Wacahootaman,

This phenomenon has occurred frequently with respect to hurricanes, as far back as Alicia (1983). In my view, the estimates as to the winds that such windows can withstand, are very likely somewhat overstated. From the actual experience of past hurricanes and the resulting damage, I believe that the estimates might be overstated by up to 1 category on the Saffir-Simpson scale. In my view, the engineering models from which the estimates are made should be adjusted as appropriate to encompass the real-world impact that has occurred in past hurricanes or at least the model bias (factor of overstatement) should be considered in the building process.

While some might be surprised by the blown out windows, I'm not. If one recalls, Katrina blew out similar grade windows even as she crossed southern Florida as a Category 1 hurricane. Given that Wilma came ashore as a Category 3 storm and exited at Category 2, the glass failure is probably par for the course.

[bevgo]

Why surprised???? Didn't they see NOLA????????

[Canelaw99]

Sure does Kevin. I have pics of my area in Homestead, but the pictures I've seen of downtown Ft. Lauderdale/Miami are amazing. It's strange to see the highrise bldgs. with windows blown out, Brickell Ave. flooded, etc. Broward Cty. courthouse is closed through this week and next. Miami is closed this week.

There are tons of trees down all over the place. Roof damage due to winds and trees. It's all over S. FL. Just wait till you're able to see some pics.

cbs4.com

nbc6.net

good places to see pics

[vbhoutex]

It sounds to me like the damage to the skyscrapers should be expected on the upper floors. With surface winds at a CAT2 or CAT3 level the winds higher up could easily have approached 150 mph. Tack on the probability of at least some shoddy workmanship and then you have debris from upper floors impacting everything around/below it.

[thermos]

They did find some flight level winds of 130-135 kt the night before the storm hit but they did not upgrade to a Cat 4. Its possible some of those winds hit the skyscrapers.

[mtm4319]

They did find some flight level winds of 130-135 kt the night before the storm hit but they did not upgrade to a Cat 4. Its possible some of those winds hit the skyscrapers.

Flight-level winds of 126 kt (which would convert to 130 mph at the surface) were found just southwest of Cape Sable just as the eye passed over Cape Romano.

[caribepr]

Read *Stormy Weather* by Carl Hiaasen about codes in Florida. Read *Condiminium* by John McDonald. Two authors whose love of Florida made use of fiction to point out some brutal truths.
But if fiction isn't interesting enough, try *Paradise Screwed* also by Carl Hiaasen, published in 2001, a compilation of columns he wrote on how things are done in the Sunshine State on a regular basis. Suprised at supposed code failures? Not this ex-Floridian (who still loves Fla, by the way).

[brunota2003]

Think about it, its not the winds you really have to worry about, its the debris, the wind busts one window, then the remains of that window plus everything on that floor go flying through the air and hit more windows, then it repeats, just with more debris being picking up every time...

[zlaxier]

The confusing thing is I don't remember Brickell receiving anywhere near this amount of window damage during Hurricane Andrew in 1992. There was some window damage but nothing like this. And during Andrew, Brickell received similar winds apparently to what was measured in Wilma in Miami. Cat 1 sustained with Cat 2/borderline 3 gusts.

So why did all the windows blow out during Wilma and not during Andrew when the codes were strengthened since then?

I think it's possible that embedded in some of the bands that hit Miami-Dade were Cat 2 and 3 and possibly Cat 4 winds slightly above the surface. Vortices of some sort maybe? It would explain that 135kts flight wind observed by aircraft right before landfall in the gulf.

[dlisted]

One factor nobody is mentioning is how fast this storm was moving. Yes there were very high winds --but one possibility is that the rapid change in pressure as the eye moved over South Florida caused some of the window damage.

Imagine if you will that the expansion space in the window frames is very minimal. As the pressure rapidly changes, coupled with the winds, the glass gives way.

Don't know if this theory holds water, but it seems logical to me.

[otowntiger]

I think it comes down to the simple fact that they over estimated the strength of the windows AND they underestimated the intensity of the winds. There is no way only 100 mph winds did that damage. It had to be much higher especially on the upper levels. I'm actually dumbfounded that Mr. Saffir himself is dumbfounded and apparently a little ignorant.

[KatDaddy]

Mr Saffir dumbfounded?! The higher up you go the stronger the winds.......its just that simple and the building codes............just how valid was the structural testing. It will be very interesting to see what studies prove. Also we must note the number microburst that occurred. Perhaps it was more turbulent a little higher off the ground. I feel there is much to be learned from Wilma.

[fci]

Hello from Naples, i'm on a laptop and w/o power atm, please forgive me making a new topic, but I was wondering how bad the damage is outside of Collier County? How is SE Florida, specifically Miami/Fort Lauderdale. We have no cable service here, and barely any phone service in the area, and the places that do have power, don't have cable or sattelite so we're practically cut off from the world right now.

All i've heard outside of Collier County is that High rises in Miami/Fort Lauderdale were blown out, dozens of them. Is this true? Also was there any other damage other than severe power outages on the East Coast? I can tell you that I will be posting images of damage in just one of the communities in SW FL, East Naples has some major damage. Does this damage spread to SE FL as well?

Thanks,
Kevin Cho - East Naples, FL
Junior: Naples High School

Kevin:
How did you and your family fare in the storm
Did y'all get the eye and if so, for how long?

[terstorm1012]

Could the front Wilma was interacting with have enhanced the vorticies? just curious.

[thunderchief]

cat 2 winds spreading over 10s of thousands of highrise glass panes amongst the largest metro area on the hurricane coast.

in all honesty, who realistically expected no window damage?